base: Redesign internal frame buffer handling

Currently, frame buffer handling in gem5 is quite ad hoc. In practice,
we pass around naked pointers to raw pixel data and expect consumers
to convert frame buffers using the (broken) VideoConverter.

This changeset completely redesigns the way we handle frame buffers
internally. In summary, it fixes several color conversion bugs, adds
support for more color formats (e.g., big endian), and makes the code
base easier to follow.

In the new world, gem5 always represents pixel data using the Pixel
struct when pixels need to be passed between different classes (e.g.,
a display controller and the VNC server). Producers of entire frames
(e.g., display controllers) should use the FrameBuffer class to
represent a frame.

Frame producers are expected to create one instance of the FrameBuffer
class in their constructors and register it with its consumers
once. Consumers are expected to check the dimensions of the frame
buffer when they consume it.

Conversion between the external representation and the internal
representation is supported for all common "true color" RGB formats of
up to 32-bit color depth. The external pixel representation is
expected to be between 1 and 4 bytes in either big endian or little
endian. Color channels are assumed to be contiguous ranges of bits
within each pixel word. The external pixel value is scaled to an 8-bit
internal representation using a floating multiplication to map it to
the entire 8-bit range.

1 files changed, 8 insertions, 25 deletions

diff --git a/src/base/vnc/vncinput.hh b/src/base/vnc/vncinput.hh
index 1686e3f25..96235fec7 100644
--- a/src/base/vnc/vncinput.hh
+++ b/src/base/vnc/vncinput.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010 ARM Limited
+ * Copyright (c) 2010, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -46,8 +46,8 @@
 #define __BASE_VNC_VNC_INPUT_HH__
 
 #include <iostream>
+#include <memory>
 
-#include "base/vnc/convert.hh"
 #include "base/bitmap.hh"
 #include "params/VncInput.hh"
 #include "sim/sim_object.hh"
@@ -160,11 +160,7 @@ class VncInput : public SimObject
      * tell us where the data is instead of constanly copying it around
      * @param rfb frame buffer that we're going to use
      */
-    void
-    setFramebufferAddr(uint8_t* rfb)
-    {
-        fbPtr = rfb;
-    }
+    virtual void setFrameBuffer(const FrameBuffer *rfb);
 
     /** Set up the device that would like to receive notifications when keys are
      * pressed in the vnc client keyboard
@@ -196,32 +192,19 @@ class VncInput : public SimObject
      * the frame buffer has been updated and a new image needs to be sent to the
      * client
      */
-    virtual void setDirty()
-    {
-        if (captureEnabled)
-            captureFrameBuffer();
-    }
-
-    /** Set the mode of the data the frame buffer will be sending us
-     * @param mode the mode
-     */
-    virtual void setFrameBufferParams(VideoConvert::Mode mode, uint16_t width, uint16_t height);
+    virtual void setDirty();
 
   protected:
+    virtual void frameBufferResized() {};
+
     /** The device to notify when we get key events */
     VncKeyboard *keyboard;
 
     /** The device to notify when we get mouse events */
     VncMouse *mouse;
 
-    /** The video converter that transforms data for us */
-    VideoConvert *vc;
-
     /** pointer to the actual data that is stored in the frame buffer device */
-    uint8_t* fbPtr;
-
-    /** The mode of data we're getting frame buffer in */
-    VideoConvert::Mode videoMode;
+    const FrameBuffer *fb;
 
     /** the width of the frame buffer we are sending to the client */
     uint16_t _videoWidth;
@@ -242,7 +225,7 @@ class VncInput : public SimObject
     uint64_t captureLastHash;
 
     /** Cached bitmap object for writing out frame buffers to file */
-    Bitmap *captureBitmap;
+    std::unique_ptr<Bitmap> captureBitmap;
 
     /** Captures the current frame buffer to a file */
     void captureFrameBuffer();